Brothers and sisters, don’t say evil things about each other. Whoever insults or criticizes a brother or sister insults and criticizes the Law. If you find fault with the Law, you are not a doer of the Law but a judge over it. There is only one lawgiver and judge, and he is able to save and to destroy. But you who judge your neighbor, who are you?

The Bible (The New Testament) (AD 1st - 2nd C) Christian sacred scripture

James 4:11-12 [CEB (2011)]
    (Source)

Alternate translations:

Speak not evil one of another, brethren. He that speaketh evil of his brother, and judgeth his brother, speaketh evil of the law, and judgeth the law: but if thou judge the law, thou art not a doer of the law, but a judge. There is one lawgiver, who is able to save and to destroy: who art thou that judgest another?
[KJV (1611)]

Brothers, do not slander one another. Anyone who slanders a brother, or condemns him, is speaking against the Law and condemning the Law. But if you condemn the Law, you have stopped keeping it and become a judge over it. There is only one lawgiver and he is the only judge and has the power to acquit or to sentence. Who are you to give a verdict on your neighbour?
[JB (1966)]

Do not criticize one another, my friends. If you criticize or judge another Christian, you criticize and judge the Law. If you judge the Law, then you are no longer one who obeys the Law, but one who judges it. God is the only lawgiver and judge. He alone can save and destroy. Who do you think you are, to judge someone else?
[GNT (1976)]

Brothers, do not slander one another. Anyone who slanders a brother, or condemns one, is speaking against the Law and condemning the Law. But if you condemn the Law, you have ceased to be subject to it and become a judge over it. There is only one lawgiver and he is the only judge and has the power to save or to destroy. Who are you to give a verdict on your neighbour?
[NJB (1985)]

Do not speak evil against one another, brothers and sisters. Whoever speaks evil against another or judges another speaks evil against the law and judges the law, but if you judge the law, you are not a doer of the law but a judge. 1There is one lawgiver and judge who is able to save and to destroy. So who, then, are you to judge your neighbor?
[NRSV (2021 ed.)]

Brothers and sisters, do not slander one another. Anyone who speaks against a brother or sister or judges them speaks against the law and judges it. When you judge the law, you are not keeping it, but sitting in judgment on it. There is only one Lawgiver and Judge, the one who is able to save and destroy. But you -- who are you to judge your neighbor?
[NIV (2011 ed.)]